From 2a6c4369be8d0522a1f439aa02bce0eb21d42ea2 Mon Sep 17 00:00:00 2001 From: Fabricio Voznika Date: Mon, 16 Mar 2020 15:59:29 -0700 Subject: Enforce file size rlimits in VFS2 Updates #1035 PiperOrigin-RevId: 301255357 --- pkg/sentry/syscalls/linux/vfs2/setstat.go | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'pkg/sentry/syscalls/linux/vfs2') diff --git a/pkg/sentry/syscalls/linux/vfs2/setstat.go b/pkg/sentry/syscalls/linux/vfs2/setstat.go index 9250659ff..136453ccc 100644 --- a/pkg/sentry/syscalls/linux/vfs2/setstat.go +++ b/pkg/sentry/syscalls/linux/vfs2/setstat.go @@ -173,12 +173,13 @@ func Truncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc return 0, nil, err } - return 0, nil, setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &vfs.SetStatOptions{ + err = setstatat(t, linux.AT_FDCWD, path, disallowEmptyPath, followFinalSymlink, &vfs.SetStatOptions{ Stat: linux.Statx{ Mask: linux.STATX_SIZE, Size: uint64(length), }, }) + return 0, nil, handleSetSizeError(t, err) } // Ftruncate implements Linux syscall ftruncate(2). @@ -196,12 +197,13 @@ func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys } defer file.DecRef() - return 0, nil, file.SetStat(t, vfs.SetStatOptions{ + err := file.SetStat(t, vfs.SetStatOptions{ Stat: linux.Statx{ Mask: linux.STATX_SIZE, Size: uint64(length), }, }) + return 0, nil, handleSetSizeError(t, err) } // Utime implements Linux syscall utime(2). @@ -378,3 +380,12 @@ func setstatat(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPa FollowFinalSymlink: bool(shouldFollowFinalSymlink), }, opts) } + +func handleSetSizeError(t *kernel.Task, err error) error { + if err == syserror.ErrExceedsFileSizeLimit { + // Convert error to EFBIG and send a SIGXFSZ per setrlimit(2). + t.SendSignal(kernel.SignalInfoNoInfo(linux.SIGXFSZ, t, t)) + return syserror.EFBIG + } + return err +} -- cgit v1.2.3